Fixes thoas#106

Author: vellotis

retrieve.go

@@ -9,7 +9,7 @@ import (
 func Get(out interface{}, path string) interface{} {
 	result := get(reflect.ValueOf(out), path)
 
-	if result.Kind() != reflect.Invalid {
+	if result.Kind() != reflect.Invalid && !result.IsZero() {
 		return result.Interface()
 	}
 
@@ -23,15 +23,19 @@ func get(value reflect.Value, path string) reflect.Value {
 		length := value.Len()
 
 		if length == 0 {
-			return resultSlice
+			zeroElement := reflect.Zero(value.Type().Elem())
+			pathValue := get(zeroElement, path)
+			value = reflect.MakeSlice(reflect.SliceOf(pathValue.Type()), 0, 0)
+
+			return value
 		}
 
 		for i := 0; i < length; i++ {
 			item := value.Index(i)
 
 			resultValue := get(item, path)
 
-			if resultValue.Kind() == reflect.Invalid {
+			if resultValue.Kind() == reflect.Invalid || resultValue.IsZero() {
 				continue
 			}
 

retrieve_test.go

@@ -12,6 +12,9 @@ func TestGetSlice(t *testing.T) {
 	is.Equal(Get(SliceOf(foo), "ID"), []int{1})
 	is.Equal(Get(SliceOf(foo), "Bar.Name"), []string{"Test"})
 	is.Equal(Get(SliceOf(foo), "Bar"), []*Bar{bar})
+	is.Equal(Get(([]Foo)(nil), "Bar.Name"), []string{})
+	is.Equal(Get([]Foo{}, "Bar.Name"), []string{})
+	is.Equal(Get([]*Foo{}, "Bar.Name"), []string{})
 }
 
 func TestGetSliceMultiLevel(t *testing.T) {
@@ -33,6 +36,7 @@ func TestGetNil(t *testing.T) {
 
 	is.Equal(Get(foo2, "Bar.Name"), nil)
 	is.Equal(Get([]*Foo{foo, foo2}, "Bar.Name"), []string{"Test"})
+	is.Equal(Get([]*Foo{foo, foo2}, "Bar"), []*Bar{bar})
 }
 
 func TestGetThroughInterface(t *testing.T) {

utils.go

@@ -77,6 +77,10 @@ func redirectValue(value reflect.Value) reflect.Value {
 			return value
 		}
 
+		if !res.IsValid() && value.Kind() == reflect.Ptr {
+			return reflect.Zero(value.Type().Elem())
+		}
+
 		value = res
 	}
 }